I found a pretty simple way to add collision to
my game. I dont know how usefull it is for other games.
I made boxes at the walls, then made them transperant and added collision.
Then I added a box with collision for the player which "followed" the player.
The it is as simple as:
if leftkey() = 1 and object collision (leftwall,player) = 0
Move object left (player)
endif
if rightkey() = 1 and object collision (rightwall,player) = 0
Move object right (player)
endif
That is one way to solve it. I bet there are hundreds of ther ways which suits you better