does it have any anti-cheat to prevent those DMers? or we have to play with honest people?

Oracle, i suggest you made revive potion, and the recipe is 1x Healing potion+ 1xblood leaf + 1xstone=1x Revive potion.
Example: player B are dead, player A can revive player B using revive potion, the player A can also using the revive potion when he dead.

~ + "DM" = HAX!

even if there is none of that , people can still code hacks , mind ya

Of course, one can still cheat. But because there are only two players and the goal of the game is to have fun, noone will hack because it would spoil the fun. Hacking cs2d makes sense because you can climb to the top of the stats whereas hacking S2MP will just make you lose a friend.