Digimon Tamers: Battle Spirit Ver. 1.5 was released exclusively in Japan for the WonderSwan Color handheld console. It expands on Digimon Tamers: Battle Spirit (released in the United States and Europe as Digimon Battle Spirit) and contains many new features and characters. Unlike its predecessor or sequel, Digimon Battle Spirit 2, this game did not receive a Game Boy Advance port.
Digimon Tamers: Battle Spirit Ver. 1.5 had a similar opening to the original game, although lengthened to contain the expanded roster (although BlackAgumon and Extra Agumon were not revealed. A shadowed Beelzemon Blast Mode is shown along with Impmon and Milleniummon
The final scene of the opening is randomly picked. The following duels could be seen at the end:
BlackWarGreymon vs. WarGreymon
MegaGargomon vs. Cherubimon
Gallantmon vs. Omnimon
Seraphimon vs. Ophanimon
Gallantmon Crimson Mode vs. Beelzemon Blast Mode
By beating the game on Normal difficulty or higher without losing, the player got a chance to battle ZeedMillenniummon as a second "final boss".
All of the original characters, including the unlockable Digimon, from Digimon Tamers: Battle Spirit were included as playable characters from the start, with the exception of Impmon. In addition, Patamon and Gatomon were added, with Seraphimon and Ophanimon as their evolutions, respectively.
In addition, there were two unlockable Digimon; An Extra Guilmon (who is unlocked by obtaining the "ultimate*" level tag in single player mode) who, like the Extra Agumon that could evolve into Omnimon, evolved into Gallantmon Crimson Mode, and the returning Impmon (who is unlocked by obtaining the "champion*" level tag in single player mode), with Beelzemon Blast Mode as a new evolution .
Three new levels were added in Digimon Tamers: Battle Spirit Ver. 1.5.:
A train level, possibly a Locomon, was included as Patamon's level. The Train had two vents on either side of the level which worked similar to the trampoline in Terriermon's level. During the match, the train passes through a modern, unnamed town. DemiDevimon are constantly flying above the fighters.
A waterfall level was included as Gatomon's level. The Digimon fight beside and behind the waterfall, with bushes here and there on the sides. Makuramon can occasionally be seen in the bushes, and Gotsumon occasionally roll down the mountain. This is the only vertical level in the Digimon: Battle Spirit series.
Instead of randomly interrupting a fight, Impmon received his own stage, which appears to be loosely based on the net from the Second Digimon Movie. Television screens of Impmon line both sides of the level, and the entire stage has an odd feel to it. Interestingly, the level is vertically symmetrical; you can see a floor above you when you're on the highest platform. The suction effect, which draws loose data to Impmon, is automatically on. There are no random enemies in this stage.
Source: Wikipedia, "Digimon Tamers: Battle Spirit Ver. 1.5", available under the CC-BY-SA License.