Slay one is one of the best io games released ever. And it's not only because of the multiple upgrading schemes or various skills and boosters, maps count and game modes. The gameplay itself is unique and exciting
How to Play Slay One
Well now on you're a newbie in Slay one. Get a look at skills tree. You've got 1200 points you can use to upgrade them. Also there's a XP counter somewhere. You receive gold for each new level up and you can spend it for upgrading your skills.
There're two main bars in the game: health and energy. Energy required to use special abilities like healing, bomb dropping, invisibility and etc. All these can be upgraded using XP points, but don't forget about Agility and Strength abilities as well. Note that Strength only increases maximum health level, not damage dealt to enemies.
In the zombie modes you can score points in game and upgrade during the game. You start as a human and if humans lose you respawn on the zombies side and your goal is to kill all humans. Also when playing for zombie you've got different skills tree.