What kind of programs would you recommend, where you can design your level in tiles and is easy to use and understand?
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Construct 2
Off the top of my head, these are some that I have found useful:
tIDE
Tile Studio
Tiled
Tiled has been my favorite one so far, specially because there's a TMX importer plugin for C2 around here.
Have fun!
I am using a free 3d application called Blender. Great for nice 3d looking tiles, and easy animated sprites.
blender.org
Neotextureedit is handy for making seamless tiles too.
neotextureedit.sourceforge.net/index.html