PortableFreewareGames.com hosts full versions of free games that require no installation. All games available through the website have been tested with Windows XP, Windows Vista, and Windows 7. (Link to Climbing the Dragon Tower)
This is the second game of mine hosted by PortableFreewareGames. In addition to "Climbing the Dragon Tower," they have also hosted Bug-Bot Blitz.
In addition to hosting "Climbing the Dragon Tower," PortableFreewareGames.com has produced a brief gameplay tutorial video explaining the game's mechanics and how to find the game on their website.
I am not associated directly with PortableFreewareGames.com and do not directly or indirectly endorse the software tools (PISA and VPN) packaged with their distribution of "Climbing the Dragon Tower."