Gladius is based in the four regions of Nordagh, Imperia, Windward Steppes and the Southern Expanse. Each of these regions consists of a few cities, each of which holds an arena for gladatorial games. The player controls a new school of gladiators with the ultimate goal of competing at and winning the High League Tournament at Clitha. Two different schools are available to players. A beginner difficulty is offered, and this follows the exploits of Ursula. An advanced school can also be chosen, and this tells the story of Valens. Either path offers a lengthy adventure, and it will take many hours to complete both storylines.

Although there exists two separate stories to play through the main focus of Gladius is not its narrative. The storylines provide a little meaning to the game but they are not the strong stories of most RPGs, nor are they the 'epic gladiatorial saga' promised by the developers. Instead the focus is on the arenas and the combat that takes place there. Most of the gameplay is pointed towards this with little room for exploration. Although it is possible to leave the paths that separate the towns little is gained from this. Certainly no new areas are opened up, or hidden spots to be found. There are a few side-quests in each region, but the completion of this generally involves more combat outside the arena so are not totally separate to the main part of the game.

Battles are a large part of any fighters life, and in Gladius there are literally dozens of them. While completing all of them is not necessary to finishing the game, most of them will need to be won by the player's school in order to progress. Several battles need to be won in each town to gain entry to that town's tournament. Win the tournament in each town, along with a few other tournaments and the player has access to the regional tournament. Win in each of the regions to gain entry to the overall tournament in Caltha. It's a fairly straightforward progression that leaves little to the imagination. While other games are quite linear, Gladius takes it to the extreme by mapping out the whole path from the outset.

The battles themselves are reasonably slow moving, turn-based affairs, with battles lasting 10 minutes or more not uncommon, and there is a fair amount of strategy iinvolved in winning most matches. Players pick a team of fighters from their school and place them on certain spots in the arena. Good fighter placement can often affect the course of the battle. From there the fighters on the field take it in turns (based on their initiative rating) to fight the other team. Various options are available to each fighter, with more attacks and moves available as the fighter gains more experience. The most common type of battle is where the objective is to defeat all the opponents. In arena battles there is no killing, so losing a battle will not end the game or cause any penalty to the player. The battle can be reselected for the player to try again to win.

There are a good range of moves to choose from, and different classes of fighter will have different moves available to them. As fighters gain experience they also gain 'job points' which can then be spent on purchasing extra actions. In addition to picking the action most of the time the player will also need to press certain buttons to time the attack. A combo move for instance can require up to four button presses in time with a swing meter at the bottom of the screen to perform them well. Well-timed presses can result in a critical hit, while mis-timing a press can often lead to either missing the attack or reducing the amount of damage inflicted. There are several types of swing meter depending on the type of attack. Although there is an option to switch this feature off and randomise the attack its a great way to make the battles more interactive and interesting, and learning to time attacks well can provide a good advantage in battle.

In addition to the straight 'defeat the enemy' type of fight there are variations to the basic battle, many of which don't involve directly killing the other team off. In King of the Hill the team that controls a certain point on the map for the longest wins. Domination is a variation on this, with several points on the map to control. Points battle is about inflicting the most damage in a certain amount of time, while other battles are about destroying the other team's statue first or breaking the most barrels in the arena. These and other types of battles help to keep the game a little more interesting. For most of them though team placement is sometimes the most important decision made for the battle. Games like King of the Hill are generally won by the first team that captures the point. This is mainly due to the slow movement of the battles, so by the time the King is killed or pushed from his spot there is so little time left in the round. Even a weaker team can win events like this if quick enough or placed better than others.

Fighters in Gladius come in a few classes, such as barbarian, thief, berserker, minotaur and even animals like bears and wolves. There is a good range to choose from. These will also make up the opposition that is faced in battle. Unlike most other RPGs Gladius doesn't feature strange or unique monsters. All of the opposition, even in the random battles outside the towns, are composed of classes that will at some stage be available to add to the player's school. While some of these opponents are quite fearsome, it doesn't quite equal the mystery and the danger faced in similar games where a large and terrifying boss appears, or where enemies are unknown. In Gladius the enemies are known elements. The player will come to intimately know each move possible, mainly because they have the same class in their school. Fighters in the game are also broken down by weight into light, medium or heavy fighters. Each type is stronger against one type and weaker against the other, quite a simplistic system, so part of choosing a team and choosing on who they should target is based on that.

As well as being defined by class and body type fighters are also know for their affinity. Affinity is a major part of the world of Gladius. The forces of light and dark, and the elemental earth, air, fire and water. Weapons and armour can be imbued with affinity with the player able to learn affinity attacks if they equip the proper weapon. While the game can quite easily be played without utilising affinity to any great extent players who take the time to learn the extra abilities and properly equip themselves will have a definite advantage in battle.

As more battles are won the more prestige the school gets. This in turn attracts more and better gladiators to sign up for the school. Part of the goal of Gladius is to build up a team of fighters that can take on a wide range of opposition teams. Fighters involved in a battle are chosen for each fight, so the team can be customised to face any competition. In practice though it is quite possible to survive by just relying on a small core team for most matches. Some battles specify which classes can and can't participate, so use of a wider team is sometimes necessary. Most of the time though only a few fighters ever need to be used.

Schools are also rated in a simple system that depends on how many regional tournaments they have won. At the start the school will be classed as amateur, and will eventually progress to semi-pro and professional. This rating is not just a label but will limit the school's members. For instance at the outset the player's school will be limited to 8 members, and those members will be limited to level 5. Although we didn't have a problem with the number of members in the school, we did find we had a problem with the level limit being quite low. It is possible to achieve a level 5 ranking for all members of the school fairly early in the game. After that fighters cannot progress to level 6 or learn any new skills until the regional tournament is won, which may take quite a bit of time. It just seems that the game is quite unbalanced in this area.

Also quite unbalanced are the battles that must be won. While the lower leagues in each town can often be quite tough to beat, and some will require revisiting later in the game when the school is stronger, both the town and the regional tournaments were fairly easy to win. Rather than being the tough boss battles against another strong school that we were expecting the major tournaments were against some quite weak opposition that were easily beaten. This was quite a letdown after some of the tough fights that we won to get there.

As well as the singleplayer game there are a couple of multiplayer modes, versus and co-op. In the versus mode players can pit their schools against each other by importing schools from another game from a memory card. In the context of the game it is a fairly limited feature, and may not have the appeal of multiplayer in other games. The co-op mode is also a nice feature to have, also again rather limited. In this mode two players take control of various gladiators within the same school. The same battles are fought as in singleplayer with the same size teams, just with two players controlling the action instead of one.

Graphically Gladius is not overly impressive. The look of the game serves it well in a functional sense, but no more. On the battlefield fighters are reasonably well done, although they lack the detail that is apparent in other games. The attacks in Gladius do not have the flashiness of other RPGs either, with only some affinity attacks approaching anything notable. Gladius is not that impressive in terms of sound either. Though there is distinctive music for each arena this can soon become a little repetetive. In the arena the sounds of battle sound quite real although a heavy, dangerous-sounding hit that only produces a couple of points of damage can sometimes appear out of place. The fighters themselves often speak warnings or warcries. These usually end up being unintentionally funny though, rather than worrying.

The presentation of Gladius is also not as good as it could have been. The menu system leaves much to be desired. For instance if a fighter levels up after a battle players will need to navigate through six screens to get to where they can purchase new skills, and then another six to get back to choosing the next battle. Also slowing the game down are the loading screens. These appear after almost every action outside a battle, and are sometimes reasonably long.