Signal Studios is best known for its pair of Xbox Live Arcade titles, Toy Soldiers and Toy Soldiers: Cold War (which it just recovered the rights to from Microsoft). The studio's upcoming mobile title is a completely different venture that invites players to toss around a sleeping, ragdoll prince.

The snoozing prince can be flung through each of 40 levels (more are being added), collecting gems, finding hidden stars, and bouncing about. It's harder than it looks, as the prince can only be controlled very slightly while he's in midair.

There are gates placed along the way, and passing through requires a specified number of stars. Expect to double back and replay levels to improve your time, collect more gems, and find the three stars.

Unfortunately, Sleeping Prince is a free-to-play title that uses the dreaded energy mechanic. It makes it hard to get enthusiastic about the title, given the time-gating that forces players to decide between spending money and waiting to play more.

Sleeping Prince has a charming premise and clever gameplay. If it were a premium title without in-app purchases, it would be much easier to be enthusiastic for its late April iOS release. The gameplay inspires repeating levels to achieve mastery. Unfortunately, knowing my play time is going to be limited by a slowly replenishing resource meter dampens my hope that this physics based title will be something that will hold my attention.