Jumpster is more than a money-making vehicle. It's actually a well thought-out platform adventure with imaginatively-designed environments and tricky stages full of cool set pieces, from spikes and breakable objects to monsters, trampolines and switches.
While I was not a fan of the freemium mechanic, you can't beat an app that's free to play. Just keep in mind that you may only be able to play this game once every few hours unless you want to spend the cash to play more often.
The level design encourages planning and more than just trial and error, the physics hit the spot and the graphics are well designed, but for anyone with an aversion for the hard sell within a game Jumpster doesn't do itself any favours.