Some additional info about openlierox's license for those who are interested.

According to the openlierox webpage, openlierox is the continuation of the
opensource release of Liero Extreme under the zlib License. Unfortunately the
sources distributed by openlierox do not seem to contain any of the original
license info other then an old readme under the original_lx_docs dir which
predates the opensource release.

Liero extreme however was indeed released under the zlib License, as is cleary
stated by its original author here:
http://forums.thegaminguniverse.com/showthread.php?t=28565

The openlierox work / extensions to Liero Xtreme are licensed under the 
GNU LGPL, see COPYING.lib . This is ok as the original zlib License is
compatible with the (L)GPL, see: http://www.gnu.org/licenses/license-list.html
This means that openlierox as a whole is properly licensed, under the LGPL.