The NIRVANA Engine is a 'bicolour' (multicolour 8×2) graphics engine written by Einar Saukas, supporting a multicolour square area of 22 character rows by 30 character columns. It's open source and royalty-free (even for commercial programs). Further details can be found in this thread. The latest version is available for download here.
It natively supports all standard Spectrum models (48K, 128K, +2, +2A, +2B, +3). It was also ported to Pentagon machines by Denis Grachev and Einar Saukas, available here. Moreover, engine logos can be obtained here.
List of released games using the NIRVANA Engine:
- DreamWalker: Alter Ego 2 by Denis Grachev & others
- El Stompo by Dave "R-Tape" Hughes
- Sun Bucket by Dave "R-Tape" Hughes
- MultiDude by Denis Grachev & others
List of games currently under development: