There are 6 different maps. These cards change every 12 levels. Each level change is preceded by a "FULL BOSS" battle. All aliens are powerful and you have to destroy them to move to a new map.
There are 4 heroes; 3 of these heroes can be purchased. The "Daily Leaderboard" is calculated at the end of the day with the "Daily Player XP" points you get at the end of the level. You can buy new characters with the "GOLD" you earn thanks to this leaderboard. This "daily leaderboard" is refreshed daily.
There are 15 sci-fi weapons; these weapons can be purchased and upgraded with in-game currency. Powerful weapons are needed to destroy powerful zombies. You can also blast zombies with the "Bazooka".
Third Person Shooter and First Person Shooter gameplay
WASD = move
Left click = shoot
Right click = change camera
U = bazooka
R = refill
C = crouch
1 2 3 = switch weapons