Opera/2 is ported to OS/2 using the Odin Project. The porters used the Odin32 API which provides the same functionality as the Win32 API and compiled the original sources from Opera under OS/2. So this means, that Opera is completely native !!
You can download the Beta version directly from Opera as WPI (WarpIn) Archive. So you need WarpIn installed on your computer! You also to install the Odin libraries, if you don't have them yet. They are not supplied with the archive right now.
In the future Opera/2 will use the OS/2 Look&Feel provided by newer Odin releases.
Read the complete press announcement on the link below.
http://www.opera.com/pressreleases/20010704.html
Source: OS/2 ORG