Jetpack 2 - by the creator of the original Jetpack
kickstarter.com
kickstarter.com
I had completely forgotten about it until I saw this Kickstarter posted this morning and I'm definitely a supporter. I would suggest you do too.
Also, if you know anyone at HalfBrick, maybe you should suggest to them that the support a project that they've borrowed the name of for their wildly successful iOS title.
Damn... I played Jetpac to death when I was a small.
(http://en.wikipedia.org/wiki/Jetpac for those who are curious)
My point was really that people often look at something and think "Oh that's easy!". But when you actually get to the real depth of the problem it's much much more complicated and fiddly and time consuming.
Off the top of my head here are a list of things you'd need to consider for developing a game: name, story/concept, title screen, credits, intro animation, implementation of gameplay/physics/loading/saving/graphics, settings / players details, user interface and GUI elements, help, input processing (mouse,joypad,joystick,touch), sound (music, ambience, effects, interface effects) ,artwork (logos, gui elements, backgrounds, sprites), repeated playability testing (is it fun, well tuned?), level creation (initial design, tweaking, testing for edge cases), utilities (level editor, sprite/animation tools), demo mode, cheats, achievements, scoreboard, installer.
And of course a game over screen.